Deleting cookies does not necessarily make a laptop or smartphone look new to an online casino. Platforms, including many of the top online casinos, can combine browser characteristics, IP data, device identifiers and behavioural signals to estimate whether a device has visited before. This process, commonly known as casino device fingerprinting, is used to protect accounts, identify suspicious activity and detect customers attempting to operate multiple accounts. However, it also raises privacy questions because the information collected is less visible than an ordinary browser cookie.
Why online casinos recognise returning devices
Online casinos need to confirm that accounts are being used by the people who created them. Identity documents and payment checks provide part of the answer, but operators also monitor the technical environment from which an account is accessed.
Device recognition can help identify situations in which:
- One person creates several accounts to claim the same promotion repeatedly.
- A customer attempts to bypass a restriction or self-exclusion.
- Stolen personal details are used to register an account.
- Someone gains unauthorised access to an existing account.
- Several apparently unrelated accounts use the same device or payment method.
- A login suddenly appears from an unfamiliar country or network.
The UK Gambling Commission warns people not to share their details for the creation of gambling accounts. Such accounts may be used to avoid restrictions, obtain additional offers or facilitate fraud and money laundering.
Technical data gives operators additional evidence, although a device match should not automatically be treated as proof of wrongdoing.
Casino cookies and browser fingerprinting
Casino cookies are small pieces of data stored in a browser. They can keep a customer signed in, remember preferences or assign a unique identifier for security and analytics.
If the user deletes those cookies, the stored identifier may disappear. Private browsing can also prevent some information from remaining on the device after the window is closed.
Browser fingerprinting takes a different approach. Instead of reading one identifier, it collects several characteristics and combines them into a technical profile.
According to Mozilla’s explanation of browser fingerprinting, the relevant characteristics can include:
- Browser type and version.
- Operating system.
- Preferred language.
- Time zone.
- Screen size and resolution.
- Installed fonts.
- Available audio and video formats.
- Browser settings and capabilities.
One characteristic is rarely sufficient to identify a device. Millions of people may use the same browser, for example. The complete combination can be much more distinctive.
A fingerprint is not always permanent or unique. Browser updates, new hardware and changes to system settings can alter it. It is better understood as a probability: the system calculates how closely the current device resembles one previously observed.
Canvas and graphics fingerprinting
Websites can also test how a browser renders graphics.
With canvas fingerprinting, the browser is instructed to draw a particular image or line of text. Small differences in the operating system, graphics hardware, drivers and fonts can produce a slightly different result. That output becomes another component of the fingerprint.
WebGL, a browser technology used for hardware-accelerated graphics, can reveal additional information about graphics capabilities and supported features.
This process does not ordinarily allow the website to see private photographs or documents stored on the device. It examines how the browser responds to a standard rendering task.
Browser developers have introduced protections against these techniques. Modern browsers may reduce user-agent information, restrict access to installed fonts or make certain characteristics less distinctive. As these protections improve, operators must rely on combinations of less precise signals rather than one supposedly permanent fingerprint.
How casinos use IP analysis
Every website receives an IP address when a device connects to it. The address can indicate the network being used and provide an approximate geographical location.
Online casinos may examine IP data to detect:
- Numerous accounts using one network.
- Logins from geographically distant locations within a short period.
- Connections associated with data centres or hosting providers.
- Networks previously connected with fraudulent activity.
- Differences between the declared location and apparent connection location.
An IP address does not identify a person reliably. Families, offices, hotels and universities can place many users behind the same public address. Mobile networks may rotate addresses or allow large numbers of customers to share infrastructure.
The same person can also appear under several addresses by switching between home broadband, public Wi-Fi and mobile data.
For this reason, IP analysis is most useful when combined with other evidence. A shared IP address alone may mean very little. The same IP, browser fingerprint, payment method and pattern of promotional activity can create a much stronger connection.
Device identifiers in mobile applications
Casino applications can access a different range of information from browser-based websites, depending on the operating system and the permissions granted.
An application may generate an installation identifier and receive details such as:
- Device model.
- Operating-system version.
- Application version.
- Language and time-zone settings.
- Security status.
- Network characteristics.
Mobile operating systems increasingly restrict permanent identifiers to protect user privacy. An app can also be reinstalled, while a phone may be reset, sold or shared. A responsible detection system therefore does not assume that one identifier always represents the same person.
It must also distinguish between a device and an account holder. Two adults in one household could legitimately use the same tablet, while one customer could access an account from several personal devices.
Behavioural signals and online casino tracking
Technical characteristics describe the device. Behavioural signals describe how it is being used.
A security system may examine login times, navigation patterns, typing speed and the time taken to complete registration forms. It can also analyse changes to passwords, addresses and payment information.
Possible warning signs include:
- Several accounts being registered in rapid succession.
- Identical information being pasted into different forms.
- A new device immediately requesting a large withdrawal.
- Multiple accounts claiming the same offer in a similar way.
- Unusually rapid actions suggesting automated software.
- A sudden change in the normal behaviour of an established account.
Behavioural analysis can help detect account takeover. If a customer normally logs in from one phone in the UK but suddenly appears on a new desktop device abroad and changes the withdrawal details, the platform may request additional verification.
Behaviour is not definitive evidence. People change devices, travel, use accessibility software and interact differently when tired or under stress. Behavioural signals should therefore trigger proportionate checks rather than automatic accusations.
How multi-account detection works
Multi-account detection generally combines connections between accounts, devices, networks and payments.
Imagine that four accounts use different names and email addresses but share the same browser fingerprint, payment instrument and home network. They were registered within one hour and all claimed the same new-customer promotion.
One similarity might be coincidental. The complete group of connections is more difficult to dismiss.
Fraud-detection systems can represent these relationships as a network. Accounts, IP addresses, devices, bank accounts and postal addresses become connected points. Closely linked clusters are then prioritised for investigation.
Shared households remain a challenge. Partners or adult relatives may have separate legitimate accounts but use the same Wi-Fi connection. Operators should consider verified identities, account history and payment ownership before concluding that their activity constitutes multi-accounting.
Does private browsing stop device recognition?
Incognito or private browsing primarily controls what remains on the device after a session. It may delete temporary cookies and browsing history when the private window is closed.
It does not necessarily hide:
- The IP address.
- Browser and operating-system details.
- Screen characteristics.
- Graphics-rendering behaviour.
- Account credentials entered during the session.
- Information already recorded on the operator’s servers.
Deleting casino cookies has similar limitations. It removes one possible identifier, but the platform can still recognise the account and compare the new session with historical device data.
A VPN changes the public IP address but usually does not change screen resolution, browser configuration, operating system or graphics characteristics. A VPN therefore does not automatically make an existing device appear new.
Privacy concerns and UK rules
Device fingerprinting can support security, but it must still comply with privacy law.
The UK Information Commissioner’s Office includes device fingerprinting among the technologies covered by its guidance on storage and access technologies. The rules can involve both the Privacy and Electronic Communications Regulations and UK GDPR when personal data is processed.
The ICO’s guidance makes clear that these requirements are not limited to traditional cookies. They can also apply to tracking pixels, scripts, web storage and fingerprinting techniques.
Operators should explain what device information is collected, why it is required, how long it is retained and whether external fraud-prevention companies receive it.
Purpose limitation is particularly important. Information collected because it is necessary for account security should not automatically be reused for advertising or unrelated personalisation. The ICO states that an organisation relying on a security-related exception must restrict the technology to that purpose.
Can fingerprinting produce mistakes?
Yes. Device recognition is probabilistic.
Browser updates can change a fingerprint, while popular devices with standard settings may resemble one another. Public networks connect unrelated users, and privacy-focused browsers can deliberately make many devices appear similar.
A false match can become serious if it causes an account restriction or delayed withdrawal. Important decisions should therefore use multiple sources of evidence and allow meaningful human review.
Customers should also have a clear way to challenge a decision. An unexplained statement that an account is “linked to another user” provides little opportunity to correct an error involving a shared household, recycled IP address or second-hand device.
Frequently asked questions
Can an online casino recognise my device after cookies are deleted?
Potentially, yes. Browser fingerprints, IP history, application identifiers, login records and behavioural signals may still connect the device with earlier activity.
Is a browser fingerprint completely unique?
Not necessarily. It is normally a probabilistic profile rather than a guaranteed unique identifier. Some devices are highly distinctive, while others share common configurations.
Does incognito mode prevent online casino tracking?
No. It limits locally stored information but does not hide account activity, IP addresses or every fingerprinting signal.
Can two people use the same device?
That depends on the operator’s terms. Two legitimate users may share a household or device, but the overlap could trigger additional verification. Each person should use their own identity and authorised payment methods.
Is casino device fingerprinting legal?
Its legality depends on the purpose, information collected, transparency and compliance with UK privacy rules. Fraud prevention does not give an operator unlimited permission to track users for unrelated purposes.
Device recognition is based on accumulated signals
Online casinos do not normally identify a returning device through one perfect digital marker. They combine several imperfect clues: browser configuration, graphics behaviour, IP history, mobile identifiers and account activity.
This approach can protect customers from identity theft and help operators detect suspicious duplicate accounts. At the same time, its hidden nature creates a responsibility to collect only necessary information, protect it properly and explain how it affects players.
A fingerprint should be treated as evidence of similarity, not automatic proof of identity. The most reliable systems recognise that distinction and combine technology with proportionate checks and genuine human review.
